Stromatolitic iron oxides: Evidence that sea-level changes can cause sedimentary iridium anomalies

Abstract

Research Article| June 01, 1991 Stromatolitic iron oxides: Evidence that sea-level changes can cause sedimentary iridium anomalies Malcolm W. Wallace; Malcolm W. Wallace 1Department of Geology and Geophysics, University of Adelaide, G.P.O. Box 498, Adelaide, South Australia 5001, Australia Search for other works by this author on: GSW Google Scholar Reid R. Keays; Reid R. Keays 2Department of Geology, University of Melbourne, Parkville, Victoria 3052, Australia Search for other works by this author on: GSW Google Scholar Victor A. Gostin Victor A. Gostin 1Department of Geology and Geophysics, University of Adelaide, G.P.O. Box 498, Adelaide, South Australia 5001, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information Malcolm W. Wallace 1Department of Geology and Geophysics, University of Adelaide, G.P.O. Box 498, Adelaide, South Australia 5001, Australia Reid R. Keays 2Department of Geology, University of Melbourne, Parkville, Victoria 3052, Australia Victor A. Gostin 1Department of Geology and Geophysics, University of Adelaide, G.P.O. Box 498, Adelaide, South Australia 5001, Australia Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1991) 19 (6): 551–554. https://doi.org/10.1130/0091-7613(1991)019<0551:SIOETS>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Malcolm W. Wallace, Reid R. Keays, Victor A. Gostin; Stromatolitic iron oxides: Evidence that sea-level changes can cause sedimentary iridium anomalies. Geology 1991;; 19 (6): 551–554. doi: https://doi.org/10.1130/0091-7613(1991)019<0551:SIOETS>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract In an attempt to understand the origin of an Ir-rich unit near the Late Devonian Frasnian-Famennian (F/F) boundary in the Canning basin of Western Australia, we have examined two lithologically similar Early Cambrian and late Oligocene age horizons from southeastern Australia. Both consist of stromatolitic iron oxide and carbonate petrographically similar to the Ir-rich Frutexites microstromatolites near the F/F boundary. Significant siderophile and chalcophile element anomalies (Ir, Pt, and Ru up to 1.1, 14, and 1.2 ppb, respectively) at both horizons have a geochemistry similar to that of the F/F Frutexites anomaly. As with the F/F bed, the Cambrian and Oligocene stromatolitic beds are closely associated with synsedimentary hardgrounds that contain evidence of subaerial exposure. We suggest that all of these Ir-rich stromatolitic beds developed in response to relative sea-level change and represent periods of condensed marine sedimentation. It is probable that condensation was produced by rapid drowning following subaerial exposure. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.